Spoilers! · 11:26pm Aug 9th, 2017
Some time ago when Twilight Sparkle became an Alicorn, there were speculation on what would happen to the main 6. Will Twilight outlive them, or they wouldn't? So then the idea for the story strike me, and the abandoned Friendship Castle was born. If MLP would be a video game then this castle is like a "Bad End" and the Friendship Era is like "The True End".